Airscrew system



Jan. 14', 1941. P. E. MERCIER I 2,228,638

AIR SCREW SYSTEM Filed July 25, 1939 4 Sheets-Sheet l IIIIIII/IIIl/IIJJ 'l NVENTOR= PIERRE ERNEST MEIRCIER ATTORNEYS Jan. 14, 1941- P; E. MERCIER AIRSCREW SYSTEM 4 Sheets-Sheet 2 INVENTOR= Filed July 25, 1939 PIERRE ERNEST ME/RCIER I byway ATTORNEY5 Jan. 14, 1941. P. MERCIER AIRSCREW SYS'iEM Filed July 25, 1939 4 Sheets-Sheet s a l In: 5? 5 n I VENTOR= IN v PIERRE ERNEST ME'RCIER ATTORNEZY5 Jan. 14, 19.41.. P. E. MERCIER AIRSCREW SYSTEM Filed July 25,1939

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PatentedJan. 14, 1941' 2,228,633" v AIRS-CREW SYSTEM Pierre Ernest Mercier, Neuilly-sur-Seine, Seine,

France Application July 25, 1939, Serial No. 286,329 In France August 17, 1938 2 Claims. .(CL-74-305).

The invention relates to airscrew systems comprising two co-axial airscrews having a zero reaction couple, the motor shaft and the assembly of the two shafts carrying the airscrews being arranged in line with one another. Such an arrangement is of particular advantage in the case of, aircraft engines having the cylinders arranged in star formation and engines having several blocks of cylinders.

9 According to one broad aspect, the invention consists in a reduction mechanism comprising in combination two symmetrical trains of straight or bevel gears, in which the torque of the motor and the reaction of the casing are equal and 5 opposite and are transmitted by the corresponding gears or satellite carriers in each of the trains, the equal .and opposite torques applied to the concentric airscrew shafts being transmitted in the same manner to the latter by the corresponding gears or satellite carriers of the two trains, thariemainirig-gears of the'said trains being connected together or being integral and being freely rotatably mounted. The hereinafter described figures of the an- D nexed drawings illustrate different embodiments of airscrew systems in accordance with the invention:

Figure 1 illustrates diagrammatically the parts I of the reduction mechanism in of the motor and the reaction to the satellite carriers;

Figure 2 illustrates a section of a complete reduction mechanism, constructed in accordance with Figure 1, with the airscrews;

which the torque torque are applied of Figure 2;

Figure 4 illustrates a reduction mechanism wherein the motor torque and the reaction torque are applied to exterior gears;

Figure 5 illustrates a variation of the construction according to Figure 4, utilizing bevel toothed pinions, the axes-oi the satellites being perpendicular to the aiis of the system;

FigureG illustrates a similar system in which the axes of the satellites are inclined to the axisof the system; v

Figure 7 illustrates a variation with two systems of satellites-mounted freelyon the samesatellite carrier lar to that illustrated in Figure 4, but in which the functions of the satellites and the internal gears have been reversed, normal straight toothed gears being employed, whilst Figure 9'illustrat'es teeth.

tween the cage by means of a stop.

tive power.

Figure 3 illustrates on a larger scale a detail g 1, integral and constitute thefmember 4. Figure 8 illustrates a reduction mechanism simi- I thereto. r

a corresponding reduction mechanism employingr bevel gears;

Figure 10 illustrates a reduction mechanism in which the motor torque and the reaction torque are applied to internal gears.

The mechanisms according to Figures 1 to 3 produce a low gear ratio, the inversion of the:

movement and the balancing of the couples ofthe airscrew by means of gears distributed in two identical and co-axial trains, each comprising an internal pinion and an arrangement of satellites themselves disposed within a gear having internal The two internal pinions of each are thus integral with one another.

of these trains I The cage of the satellites of one of the trains is secured to the motor is statigpary or prevented from rotation by an shaft. The other cage elasticconn'ection, damped or not, arranged be- I and tbe'casing of the'reduction mechanism. It could Each of the air-screw shaftsof the gears having internal teeth.

The change of pitch of one of the airscrews may, moreover, besubordinated to, the conditions of operation of, the other airscrew by means of direct subjection The pitch of the front airscrew can also bacontrolled by a known pitch control mechanism in.

also be rendered immobile is secured to one or with the introduction of mouse on the motor actuated propellers usually employed with a single airs'crew. Finally, it is readily possible, by release of the train of gears which is normally stationary relatively to the casing to, render the two airscrews independent of the motor shaft, in other words to render them free," in order to reduce, as is well known, the resistance which-they ofier to travel when flying with their driving motor not operating. :This last arrangement is of great importance in the case of multi-engine aircraft.

's liberation-of the airscrews maybe obtained by freeingacatch, by releasing a brake, or by any other appropriate means.

In-Figure 1, the motor shaft I drives the satellite carrier 2, one of the satellites being indicated The ram. sit-" leaned we ,the airsc'rew- Since the two gear trains are identical, the torques applied to the shafts 8 and 9 are equal and opposite, whatever the direction of rotation of the motor shaft.

In Figure 2 similar parts are designated by the same reference numerals.

, Ball bearings I and ill take up the traction of the airscrews and convey it to the casing of the reduction mechanism. I2 indicates the hub of the rear. airscrew which is of fixed pitch. [3 indicates the hub of the front airscrew, the pitch of which is controllable. arranged in the casing for the liquid for controlling the changing of the pitch of the front airscrew.

In the construction illustrated in Figure 3, the chamber 28 is integral with the hub of the front airscrew; the chamber 2| is integral with the motor shaft and, by means of the port 23, communicates with the tubing l5 secured to the casing; v

The tube I4, by means of the port 22, communicates with the tube 24, inside the motor shaft, which communicates with the tube 26, inside the front airscrew shaft, the tube 24 extending through the stufling box 25. The chambers 2I- and 28 are connected by the cylindrical extension 21, rotatably mounted in the stufllng box 28.

The object of Figures 4 to 7 is to illustrate the general methods of construction, ensuring the equality of the torques in, accordance with the invention, for obtaining gear reductions greater than or equal to 1:2, whilst the constructions alreadydescribed, particularly in the case where the airscrew shafts and the motor shaft are, as shown in Figures 1 and 2, arrange in line with one another, only allow smaller gear reductions.

The mechanism according to Figure 4 comprises in a casing 40, independently manufactured but fixed on the motor casing, or manufactured in one.

piecewith said casing, a driving shaft l secured to a toothed crown engaging with satellites, such as 35, the satellite carrier 34 being keyed on the shaft 9 of one of the airscrews.

The satellite carrier 38 is secured to the shaft 8 carrying the other airscrew, its satellites, such as 38, gear on the one hand with the toothed crown secured to the fixed casing 39, and on the other hand with a double central gear 31 forming a part of the two twin planetary trains.

The torque of the motor, instead of being applied to a satellite carrier, as in the case of Figure 1, is applied to one of the internally toothed gear crowns, whilst the reaction torque on the casing is transmitted thereto by the second internally toothed gear crown;

Whilst in the preceding construction the air-- diameters of the gears and is always less than 1:2, whilst in the preceding case it was always greater than this limit.

The same principle of construction may be employed when using bevel pinions.

Figure 5 illustrates a construction correspondazaaese Tubes 14 and I5 are the speeds of rotation of the airscrews and the speed of the driving motor shaft depends upon the respective ing to the embodiment with not inclined satellite carriers.

The driving shaft l is integral with a conical toothed crown gearing with satellites, such as 44, of which the satellite carrier 42 is secured to rotate with the shaft 9 of the airscrew 52. The satellites 44- gear on the other hand with a double gear 45 mounted freely on the shaft 9 and which in turn gears with the satellites 41, the satellite carrier shaft 46 of which is secured to rotate with the shaft 8 of the airscrew 5!.

The satellites 41 also gear with the toothed crown 49 secured to the fixed casing 40.

The motor torque is applied to the shaft l, whilst the reaction to the torque of the motor is transmitted to the casing 40 by the gear 49. It can be readily demonstrated that the forces applied to the satellite carriers 42 and 46, are, as in the con struction illustrated in Figure 4, equal in absolute value and opposite in direction, if the gears and their diameters are symmetrical in relation to the double gear 45.

The ratio of the mean gear reduction is in this case equal to 1 :4. It is possible to obtain different reduction gear ratios, greater or smaller than this value by symmetrically inclining the axes 'of the satellites on the satellite carriers.

For example, Figure 6 illustrates the case of a reduction mechanism with a mean reduction ratio greater than 114 and of the order of 1:3. The references on this figure are the same as in Figure 5 and another explanation is unnecessary.

Finally, in order to obtain definitely a reduction ratio of 1:2, one of the embodiments already described may be simplified by mounting the two systems of satellites freely on the same satellite carrier. This has been diagrammatically illustrated in Figure 7.

The driving shaft I is integral with a toothed crown which gears with the satellites, such as 54, which react on the toothed crown 56 secured to the casing, The satellite carrier 53 also carries other satellites, such as 55, which gear on the one hand with a pinion 6| carried by the airscrew shaft 9, and on the other hand with the double gear 60 mounted freely on the shaft 9. The gear 60, by means of its second set of teeth, gears with the satellites 58, the axes of which, such as 51, being rigidly secured to the fixed casing.

The satellites, such as 58, engage on the other hand with a pinion 59 secured to the shaft 8 of the second airscrew. The satellite carrier 53 is drivenv by the shaft l at half the motor speed, and the satellites 55 cause equilibrium of the torque between the shaft 9 and the double gear 69, which through the reversing gearing 58 drives the second airscrew in the desired direction.

It will be understood that all the mechanisms described may form an integral part of the motor casing or constitute separate units, mounted flexibly or rigidly on extended walls of the motor, or rigidly on a special framework, the motor torque being transmitted from the motor shaft to the shaft entering the reduction mechanism by means of a rigid or flexible coupling.

According to an embodiment illustrated more particularly in Figures 8 and 9, the satellite carriers may perform the function of the coupled gears of the preceding examples.

This arrangement has the advantage of providing scales of reduction complementary to the other examples already given, and in particular allows of obtaining with bevel pinions and not inclined satellite carriers the reduction ratio of 1:2.

Figure 8 corresponds the case where cylinthereof onwhich is centred another-pinion I01,

drical pinions are employed. The motor torque is applied to an internally toothed gear I I.

The reaction to the fixed casing is transmitted by anidentical gear I2.- The satellite carrier I3,

mounted freely in the mechanism, carries satellites, such as I4 and I5, which are not keyed on their common axle. The inner gears I6 and I1 are respectively secured to the airscrew shafts 8 and S.

Figure 9-illustrates the use of bevel pinions. The motor torque is applied to the gear crown iii: the reaction on the fixed casing is transmitted by the gear crown 82. The satellite carriers of the two' planetary systems 83 and 83' are freely mounted and connected to one another; their pinions, such as 84 and 85 gear with the gear crowns 8| and 82 on the one hand and with the opposite gear crowns 8G and 81 on the other hand, which are respectively secured to the airscrew shafts 8 and 8.

It will be understood that in the case of Figure 9, on inclining inwardly or outwardly the axes of the satellite pinions it is possible to vary the mean reduction ratio of the mechanism. The same result can be obtained, in the case of Figure 8. by varying the ratio of the diameters of the cylindrical gears and their satellites.

The construction according to Figure 10 illustrates that without exceeding the scope of the invention it is possible:

(1) To transfer the function of the inner gears to the satellites and the internally toothed gears;

(2) More generally, to obtain special reduction ratios, it is'possible to engage one or the other of the gears with double satellites, each elementary satellite of such coupled pinions being in engagement with one or the other of the-inner gears and the internally toothed gears;

v (3) In order to obtain on the other hand a certain flexibility in the drive of the airscrews,'the

satellite pinions of each pair may be connected to rotate together by a flexible connection, for example, of the torsion bar type.

In Figure lO the end of the crankshaft is illustrated at 9| and the motor casing at 92. The freely mounted cage'of the satellite carriers comprises two twin pieces 93 and 84, and the closing plates and, 9B, the whole being'centred on the ball bearing 91 and the needle bearing 88. The part SI carries the keyed-on sleeve I00 which, by a toothed ring IOI, sets in rotation a central motor gear 99, guided in the cage of the satellite carriersby the needle rollers I02-I 03. The other innergearing I04 is stationary and integral with the fixed casing.

Each double satellite is formed as. follows:

It comprises a pinion I05 and an extension I06 a torsion bar I08 connects I05 and'I0I.

The pinions, such as I01, drive the airscrew shafts 8 and 9 by means of the internally toothed gears I09 and H0.

What I claim'as my invention and desire to secure by Letters Patent of the United States is:

l. Mechanism for the transmission of movement between the shaft of an aircraft motor and two airscrews rotating in opposite directions and mounted on two co-axial shafts arranged in line with the motor shaft, comprising a systemof gears composed of two symmetrical trains, each train comprising at least three elements corresponding respectively with elements of the other train, one

for rotation the pinions of these elements being formed by a satellite system, means for applying the torque of the motor shaft to an element of one train belonging to a first pair of corresponding elements, means for connecting through a flexible connection to a fixed point in relation to the motor the element of the second train belonging to the said first pair, means for the transmission to the airscrew shafts of the forces of a second pair of corresponding elements; and means for connecting together the corresponding elements other than those which belong to the two above-mentioned pairs, these elements .which are connected together being mounted in such a manner as to rotate freely around the axis of the airscrew shafts.

2. Mechanism for the transmission of move ment between the shaft of an aircraft motor and two airscrews rotating in opposite directions and mounted on two co-axial shafts arranged in line with the motor shaft, comprising a system of gears composed'of two symmetrical trains, each' train-comprising at least three elements correspending-respectively with elements of the other train, one of these elements being formed by a satellite system composed of several pinions connected together through an elastic connection,-

means for applying the torque of the motor shaft J to an element of one train belonging to a first pair of corresponding elements, means for connecting to a fixed point in relation to the. motor the element of the second train relating to the said first pair, means for the transmission to the airscrew shaft of the forces of a second pair of corresponding elements, and means for connecting-together the corresponding elements other than those these elements which are. connected together being mounted in such a manner as torotate freely around the axis of the airscrew shafts.

PIERREERNEST which relate to the two above-mentioned pairs, 

